HGR Linear Guideway load capacity curves: a practical guide from principle to application
As a supplier of HGR linear guides, we often encounter confusion from our customers about the load capacity curve. This curve is a key basis for determining the suitability of a guide for a specific application. In this article, we will use easy-to-understand language to dismantle the logic behind the curve and help you quickly grasp the key points of selection.
First, recognize the load capacity curve: core elements and intuitive understanding
The load capacity curve of HGR linear guide is a chart that shows the relationship between the load capacity of the guide and the working conditions. It is like a "performance map" that tells us how much the guide rail can "carry" in different scenarios.
(1) The "language" of the curve: the meaning of the coordinate axis
Vertical axis (vertical axis): indicates the size of the load that the guideway can withstand, the unit is usually Newton (N) or kilonewtons (kN). The higher the value, the greater the weight or force that the guide can withstand.
Horizontal axis (horizontal axis): indicates the factors affecting the load capacity, common:
Running speed: how fast or slow the guideway slider moves (unit: meters / minutes). The faster the speed, the lower the load capacity of the guideway may be.
Ambient temperature: the temperature of the working environment (unit: ℃). The higher the temperature, the more obvious the load capacity of the guideway may decrease.
Preload level: the degree of compression on the balls inside the guideway (light, medium and heavy preload). The higher the preload, the more rigid the guideway is, but the less additional load it can withstand may be.
(2) The "secret" of curve trends
The effect of speed on load:
As the rail runs faster, friction increases, leading to increased heat and wear. Just as the faster a person runs, the less weight they can carry at the same time, the load the rail can carry at high speeds decreases. For example, the same rail that can carry 1000N at low speeds may only be able to carry 800N at high speeds.
Temperature impact on the load:
High temperatures can cause the guideway material to become soft and the lubricant to fail. Imagine, high temperature metal will "soften", the guide is naturally more difficult to withstand heavy loads. For example, a rail that can carry 1500N at room temperature may only be able to carry 1000N in a 100°C high temperature environment.
The effect of preload on the load:
Preload force is like "advance pressure" to the guideway, which can improve precision and rigidity, but will also "take up" part of the load carrying capacity. Light preload when the guide is more "good" at bearing weight, heavy preload is more "good" at maintaining stability, suitable for high-precision scenarios.
Second, how to use the curve to match the actual application?
Step 1: Define the working conditions of the equipment
First of all, you need to understand the key parameters of your equipment in operation:
Maximum load: the total weight or force that the guideway needs to withstand (e.g., the weight of the workpiece, the force generated by machine vibration, etc.).
Operating speed: whether the guideway is moving slowly (e.g. machine tool fine-tuning) or quickly (e.g. high-speed handling in automated production lines).
Ambient temperature: whether to work in high temperature (such as near the oven), low temperature (such as cold storage) or room temperature environment.
Accuracy requirements: whether the guideway needs to be very stable when moving (e.g. precision instruments), which will affect the choice of preload.
Step 2: Find the corresponding data from the curve
Take a common HGR20 guideway as an example, and assume that your equipment needs to run at medium speeds at room temperature, with medium preload:
Find the point in the curve that corresponds to the medium speed and check the value of the load capacity at this point (e.g. labeled 12kN).
Due to the medium preload, the curve may show a lower load capacity than the light preload (e.g. 10.2kN with a 85% discount).
Check that this value is greater than the actual load on your equipment (e.g. if your load is 8kN, then 10.2kN is sufficient).
Step 3: Allow enough safety margin
In order to ensure the long-term stable operation of the rail, it is recommended to choose a model whose load capacity is significantly greater than the actual load. For example:
Ordinary scenes: the load capacity of the rail should be at least 1.5 times the actual load.
High-impact or high-precision scenarios (e.g., stamping machines, medical equipment): it is recommended to reach more than 2 times.
Third, the selection of skills: the application of curves in different scenarios
(1) Comparison of the performance of different models of guide rail
When you need to choose among several types of guide rails, you can compare them visually through the curve:
Light load scenarios (such as 3C products conveyor belt): Priority to choose a small size guide rail (such as HGR15), the curve shows that its load capacity at low speeds is sufficient, and the cost is lower.
Heavy load scenarios (e.g., large machine tools): choose large-size guideways (e.g., HGR45), the curve shows that it can still maintain high load capacity at high speeds and high temperatures.
(2) Response strategies for special environments
Dusty environment: Dust will aggravate the wear of the guideway, so you need to choose the type of guideway with dust-proof device, and reduce the load by about 10% on the basis of the curve suggestion.
Vacuum or clean environment: ordinary grease is not suitable, need to change to special coating or solid lubrication, at this time the load capacity in the curve may need to be adjusted accordingly (usually slightly lower).
Low-temperature environment: choose low-temperature resistant grease, the curve shows a smaller decrease in the load capacity of the guideway (usually 5-10%).
Frequently Asked Questions and Pit Avoidance Reminders
1：Why is the load value on the sample different from the actual use?
A: The data in the sample is usually tested under ideal conditions (such as low speed, room temperature, light preload), and the actual use should be adjusted according to the curve combined with specific working conditions. For example, the HGR30 rail in the sample is labeled with a dynamic load of 25kN, but in a high-speed and high-temperature environment, the actual available load may only be 20kN.
2: The more the preload is selected, the more durable the rail is?
A: No. Heavy preload will make the guideway more "hard", suitable for scenarios requiring high precision (such as precision machining), but will sacrifice part of the load capacity, and may cause more heat due to increased friction. If your equipment mainly "carries heavy loads", light preload is more suitable instead.
3: How do I quickly get a curve specific to my equipment?
A：Contact us to provide the following information:
・Method of mounting the guideway (horizontal or vertical), number of sliders;
・Detailed working speed, temperature and load type (static or dynamic load);
Our engineers will provide customized load capacity analysis and selection suggestions according to your needs.
V. Get professional support now
If you still have questions about the load carrying capacity curve of HGR linear guide, or need to select a model according to specific working conditions, welcome to contact us through the following ways:
📞 Technical hotline: +86-8613116375959
📧 Mail inquiry: 741097243@qq.com
🌐 Official website: https://www.automation-js.com/
The load capacity curve is the "compass" for selecting HGR linear guides, and mastering it will prevent equipment failure or wasted performance due to improper selection. Contact us today and let a team of professionals help you find the most suitable guideway solution!
